scholarly journals The Role of O-GlcNAcylation for Protection against Ischemia-Reperfusion Injury

2019 ◽  
Vol 20 (2) ◽  
pp. 404 ◽  
Author(s):  
Rebekka Jensen ◽  
Ioanna Andreadou ◽  
Derek Hausenloy ◽  
Hans Bøtker

Ischemia reperfusion injury (IR injury) associated with ischemic heart disease contributes significantly to morbidity and mortality. O-linked β-N-acetylglucosamine (O-GlcNAc) is a dynamic posttranslational modification that plays an important role in numerous biological processes, both in normal cell functions and disease. O-GlcNAc increases in response to stress. This increase mediates stress tolerance and cell survival, and is protective. Increasing O-GlcNAc is protective against IR injury. Experimental cellular and animal models, and also human studies, have demonstrated that protection against IR injury by ischemic preconditioning, and the more clinically applicable remote ischemic preconditioning, is associated with increases in O-GlcNAc levels. In this review we discuss how the principal mechanisms underlying tissue protection against IR injury and the associated immediate elevation of O-GlcNAc may involve attenuation of calcium overload, attenuation of mitochondrial permeability transition pore opening, reduction of endoplasmic reticulum stress, modification of inflammatory and heat shock responses, and interference with established cardioprotective pathways. O-GlcNAcylation seems to be an inherent adaptive cytoprotective response to IR injury that is activated by mechanical conditioning strategies.

2018 ◽  
Vol 315 (5) ◽  
pp. H1215-H1231 ◽  
Author(s):  
Kerstin Boengler ◽  
Günter Lochnit ◽  
Rainer Schulz

Several interventions, such as ischemic preconditioning, remote pre/perconditioning, or postconditioning, are known to decrease lethal myocardial ischemia-reperfusion injury. While several signal transduction pathways become activated by such maneuvers, they all have a common end point, namely, the mitochondria. These organelles represent an essential target of the cardioprotective strategies, and the preservation of mitochondrial function is central for the reduction of ischemia-reperfusion injury. In the present review, we address the role of mitochondria in the different conditioning strategies; in particular, we focus on alterations of mitochondrial function in terms of energy production, formation of reactive oxygen species, opening of the mitochondrial permeability transition pore, and mitochondrial dynamics induced by ischemia-reperfusion.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Jinkun Xi ◽  
Yonggui He ◽  
Shuo Fei ◽  
Huan Zheng ◽  
Zhelong Xu

While the role of endoplasmic reticulum stress (ERS) in myocardial ischemia/reperfusion (I/R) injury has been extensively investigated, the precise mechanism by which inhibition of ERS induces cardioprotection remains unclear. We aimed to explore the mechanism of ERS inhibition-induced cardioprotection against I/R injury, focusing on the role of Zn 2+ and the mitochondrial permeability transition pore (mPTP). Exposure of H9c2 cells to 800 μM H 2 O 2 for 20 min increased GRP78 and GRP94 expressions (296.2 ± 41.0 and 150.6 ± 13.5 %, respectively), suggesting that H 2 O 2 can induce ERS. Cells treated with H 2 O 2 showed a significant decrease (40.6 ± 7.4 %) in TMRE fluorescence compared to the normal group (92.6 ± 0.1 %), indicating that H 2 O 2 can induce the mPTP opening. In contrast, ERS inhibitor TUDCA (30 μM) prevented the loss of TMRE fluorescence (77.8 ± 6.8 %), implying that inhibition of ERS can prevent the mPTP opening. This effect of TUDCA was blocked by zinc chelator TPEN (37.7 ± 13.0 %), indicating a role of Zn 2+ in the action of TUDCA on the mPTP opening. In support, TUDCA increased intracellular free zinc, as indicated by a marked increase in Newport Green DCF fluorescence intensity. In isolated rat hearts, GRP78 expression was not increased during ischemia but was increased upon reperfusion (1.3, 1.5, 1.9, and 1.6-fold increases at 10, 30, 60, and 120 min of reperfusion). Hearts treated with TUDCA showed a significant reduction of GRP78 expression 30 and 60 min after the onset of reperfusion, an effect that was reversed by TPEN. The immunofluorescence study also showed that the effect of TUDCA on GRP78 expression was reversed by TPEN. TUDCA reduced infarct size, and this was reversed by the mPTP opener atractyloside, indicating that ERS inhibition may protect the heart by modulating the mPTP opening. Experiments with transmission electron microscopy and hematoxylin-eosin staining revealed that TUDCA prevented endoplasmic reticulum and mitochondrial damages at reperfusion, which was blocked by TPEN. In conclusion, reperfusion but not ischemia initiates ERS and inhibition of ERS protects the heart from reperfusion injury through prevention of the mPTP opening. Increased intracellular free Zn 2+ accounts for the cardioprotective effect of ERS inhibition.


2009 ◽  
Vol 297 (4) ◽  
pp. H1487-H1493 ◽  
Author(s):  
Giuseppe Petrosillo ◽  
Giuseppe Colantuono ◽  
Nicola Moro ◽  
Francesca M. Ruggiero ◽  
Edy Tiravanti ◽  
...  

Melatonin, a well-known antioxidant, has been shown to protect against ischemia-reperfusion myocardial damage. Mitochondrial permeability transition pore (MPTP) opening is an important event in cardiomyocyte cell death occurring during ischemia-reperfusion and therefore a possible target for cardioprotection. In the present study, we tested the hypothesis that melatonin could protect heart against ischemia-reperfusion injury by inhibiting MPTP opening. Isolated perfused rat hearts were subjected to global ischemia and reperfusion in the presence or absence of melatonin in a Langerdoff apparatus. Melatonin treatment significantly improves the functional recovery of Langerdoff hearts on reperfusion, reduces the infarct size, and decreases necrotic damage as shown by the reduced release of lactate dehydrogenase. Mitochondria isolated from melatonin-treated hearts are less sensitive than mitochondria from reperfused hearts to MPTP opening as demonstrated by their higher resistance to Ca2+. Similar results were obtained following treatment of ischemic-reperfused rat heart with cyclosporine A, a known inhibitor of MPTP opening. In addition, melatonin prevents mitochondrial NAD+ release and mitochondrial cytochrome c release and, as previously shown, cardiolipin oxidation associated with ischemia-reperfusion. Together, these results demonstrate that melatonin protects heart from reperfusion injury by inhibiting MPTP opening, probably via prevention of cardiolipin peroxidation.


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